Germicidal UV – Beyond the Hype

Posted by GM Admin

Posted in Lighting Tidbits

August 18, 2020

As we find ourselves in the midst of a global pandemic, the lighting industry is working to find solutions for a Post-COVID world.

Light Fixture and Lamp Manufacturers have been touting their Germicidal-UV (GUV) lighting technologies. We at GMLD have seen images in GUV marketing materials of typical office spaces and group meeting environments, with the implication that the technology is ready for use in these applications.

Please note that we are not experts in the germicidal application of light, but we have been researching what is commercially available and in development, in order to protect and educate our clients. As professional lighting designers, we have a background in lighting and UV terminology that allows us to understand many of the important considerations.

This is a very brief rundown of what we at GMLD understand at this time. We will direct our readers to the very informative Illuminating Engineering Society’s FAQ page that has been set up for specifically this topic if you would like to learn more, or please get in touch if you would like assistance navigating the Germicidal UV landscape.

An Overview of Germicidal UV (Updated in June 2020):

  1. Radiation from lamps in the UV-C range can be a good disinfection technique. 
    1. This is most commonly used to disinfect air, either in ductwork or in ‘upper room’ UV light disinfection, where special fixtures illuminate parts of the room above the heads of users in a very controlled fashion, to disinfect room air without exposing users to harmful radiation.
  2. UV-C can be used to disinfect surfaces with direct light, and will inactivate viruses such as Covid-19.
    1. People cannot safely be in the space when this occurs, or they will suffer radiation burns to the cornea and other potential health impacts.
    2. We do not believe that typical architectural occupancy sensors or similar devices provide the appropriate level of safety required to safely mitigate UV-C exposure.
  3. Other wavelengths of light that are safer for human exposure, including near-UV and deep violet, do not have sufficient germicidal effectiveness at reasonable light level applications. 
    1. In effect, you would need so much of this near-UV light for such a long time period that it would not be a reasonable application.  And you would still not want anyone to be exposed to it for safety reasons (humans should not be disinfected with light).
    2. UV-B light can also be effective, but it can damage human health more readily, as it penetrates skin more deeply.

Given currently available products and technologies, we at GMLD do not anticipate that permanently installed Germicidal UV will be a viable option for normal office or retail environments in the near future, as the safety concerns appear to outweigh the benefits. 

As a note – Upper Room GUV has the potential to be effective in higher ceiling, high density spaces such as shopping mall food courts, lobbies or other similar spaces.  Some special conditions may be considered for surface disinfection, such as bathrooms that can be locked out during radiation exposure.  Robots with high-powered GUV lights may be effective.  We expect that ducted GUV systems or air cleaners will be a safer, more effective approach for commonly inhabited spaces. 

Diagram explaining Upper Room Germicidal UV (via IESNA GUV FAQ)

We at GMLD would be happy to assist you in reviewing any potential application of Germicidal UV proposed to you by a manufacturer. We will help you ask the right questions and find the best solutions. Please get in touch!


IESNA Main topic page (with webinar)

IESNA Simplified FAQ page